Flattening of extruded stiffened sheets



Oct. 26, 1954 G. (20220 2,692,421

FLATTENING OF EXTRUDED STIFFENED SHEETS Filed D60. 22, 1951 2 Sheets-Sheet l 5 7 M ma x N\ m6 m m M m H mw a P V. B

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Oct. 26, 1954 s. cozzo 2,692,421

FLATTENING OF EXTRUDED STIFFENED SHEETS Filed Dec. 22, 1951 2 Sheets-Sheet 2 Patented Get. 26, 1954 FLATTENING 0F EXTRUDED STIFFENED SHEETS Giuseppe Cozzo, Yonkers, N. Y., assignor to Hydropress, Incorporated, New York, N. Y., a corporation of Delaware Application December 22, 1951, Serial No. 262,987

(01. 2ii--i55) 6 Claims.

This invention relates to the making of flat integrally stiffened sheets and particularly to flat sheets made from tubes having ribs integrally joined thereto.

Integrally stiffened sheets are ones having a plurality of ribs projecting from the flat portion of the sheet, said ribs usually being substantially parallel to each other and having a flange. The integrally stiffened sheets can be used for numerous purposes where a light weight yet stiff panel or sheet is needed. As an example, such a sheet finds use in the wing of an airplane, truck panels, and other similar uses. The sheets can be made of a light metal. One of the problems involved in the forming of such a sheet is that of making it so that it is perfectly flat. When the T-shaped ribs thereon are integral with the metal of the flat portion of the sheet, such eliminates riveting or similar joining operations. One of the biggest problems is that of making the sheet so that it will be substantially flat where the rib joins the flat portion of the sheet.

One of the objects of the present invention is to form integrally stiflened sheets which will be substantially flat when finished.

Another of the objects of the invention is to provide an improved method of making integrally stiffened sheets from tubes.

In one aspect of the invention, a shaped tube can be formed by extruding metal through a suitable die, the extruded tube having radially projecting ribs extending longitudinally along the tube. The ribs can be made the size and shape to produce the desired ribs in the finished sheet. The ribs may have webs joined to the sheet and a flange.

The extruded tube can be fed into a tube advancing means which moves the tube into a slitter which cuts through one side of the tube. The slit tube then can be fed through one or more opening roller die means which can be arranged to progressively change the shape thereof from that of a tube to that of a flat sheet.

The flattened sheet then can be fed to a special roller die arrangement for particularly flattening the sheet adjacent the ribs. This last mentioned roller die arrangement can have a backing roller or guide arranged so as to bear on the flat side of the sheet opposite the rib side and can have recesses or annular spaces opposite the ribs.

Roller means may be provided bearing on the ribbed surface side of the flat sheet, these rollers at least bearing on the surface closely adjacent where the webs of the ribs join the sheet. Rolls for the rib flanges can be provided for exerting pressure on the top of the rib or flange, the flange roller pressing its flange and web toward the recess or annular space of the backing roller. This will serve to flatten the area adjacent the web joint.

The flattened sheet then can be passed through a special pulling and pushing roller die means. Next, the sheet can be flexed in a flexing roller die means to overcome residual bending. This die means is for the purpose of neutralizing the tendency of the flattened sheet to return to its curved shape. Preferably, the flexing roller die means is constructed so as to be adjustable in accordance with the particular material and sheet involved.

These and other objects, features, and advantages of invention will become apparent from the following description and drawings.

In the drawings:

Fig. 1 shows a fragmentary side view partially in section of one form in which the invention can be arranged and carried out.

Fig. 2 is an enlarged sectional View of one type of tube from which integrally stiffened sheet can be made.

Fig. 3 is an enlarged fragmentary view of one of the progressive opening roller arrangements, such as the one indicated at line 33 of Fig. i.

Fig. 4 is an enlarged fragmentary sectional view of the rib area flattening roller die located at line 4-4 of Fig. 1.

Fig. 5 is an enlarged schematically illustrated pulling and pushing roller die mechanism, such as can be located at line 55 of Fig. 1.

Fig. 6 is an enlarged fragmentary view of the flexing mechanism as can be located at line 6-6 of Fig. 1.

The sheet can be made from a tube formed in suitable extrusion machines. As an example, the metal involved can be aluminum, aluminum al- 10y, or other light-weight alloy or metals. The radially projecting ribs are made of such dimensions that when the tube is flattened, the final sheet will have the desired characteristics and dimensions. In Fig. 2, one form of tube shape is shown at iii which can have radially extending or projecting ribs ii integrally formed with the walls 12 of tube ill. Ribs i i may have webs i 3 joining the flanges M to the wall E2 of the tube.

The tube it can be fed into the arrangement of Fig. 1 in any suitable manner such-as over the rolls of conveyor !5 into the feed pinch rolls it. A suitable cutter i7 slits the wall of the tube and wedge It tends to open the tube.

A succession of opening roller die means 9A- 19F, inclusive, then can be located along the machine for the purpose of flattening the tube. One or more such opening means can be used as needed. As an example of one form of opening means, reference may be made to Fig. 3 wherein the upper rolls 20 can be located on shaft 2| which can be suita'bly'driven. Rolls :22 can be located oneither side- 0f the center group of rolls, rolls 22 being mounted on driven shafts 23 schematically shown in Fig. 3. Rolls 28 pass between ribs H and bear on the upper surface of the flat portion of the sheet. "Abacking roll 24 can be mounted on shaft 25, said backing roll not being driven. Edge supports 26zcan be mounted on shafts 21 on either sideofi-the sheet. The opening rolls IBA through 19F are arranged suitably and are constructed so that the parts have the correct relationship to each other, and so that at I9F the sheet will be substantially flat and ready to pass to special roller die means for completing the flattening of the sheet.

:The roller die means at 44 of-Fig. 1- has roll means between each of the webs. In: one form, eachbracket 28'thereof-can be fastened on a mechanism (not shown) for moving it in the direction of arrows'29. Bracket'ZS carries a shaft 30 mounted in suitable bearings-3 I,'said"bearings being in the form of needle'bearings, or the like. At the ends of shaft--30, formed rolls :32 canbe arranged so that they will, press the upper face 33 of the-flattened wall or flat sheetportionof I2 at a point close to web 13 of rib I I. A backing roll 34 may have annular recesses -34Alocated under each of thewcbs' l3. 'Ribor flange roll means 35 can be suitably mounted on a shaft (not shown) which canbepressed downwardly on flanges M of: ribs ll. Itcan be theorized: that because of thepressure'exerted on the ribs and the recesses thereunder, in conjunction with the closeness of roll means 32 to the joi-nder ofthe webs with-the flat portions of the sheet, that the metal will be shaped in .these 'areas in a manner that-will'result in a substantially flat sheet. In-v other words, the I metal of"thecsheet close to the web junction will be formedinto a substantially flat shape.

At the next station in Fig. .l, a pinch roll-sheet moving arrangement, such as illustrated in Fig. 5, can' -be'employed. In the'form shown,two sets of drive roll means are employed'it' being understood that any number can-beused or that they can be located as'needed. -Rolls tfi -are'"mounted onshaft 3'l which can -be-driven by suitable driving mechanism. "Rolls flfi-ext'end between the ribs and'grip the flat portion of the sheet between them-and the backing rol138. '-Backingro1l 35 can be carried on shaft 39.

The flattened sheet'can' be moved from "driving mechanism rolls 36 toan-adjust'able'flexing roller die means for overcoming residual bending or the tendency of the sheet to return to theoriginal tube shape. One form "of suc'h'a'means isillustrated in Fig. 6' and can be located'at line 6 6. Each of the'upper rolls lflcan 'be carriedon a shaft 4| mounted in'a bifurcated arm 42. Arm ifz'may'be adjustably' carried by oke-4s, the arm beingadjustably mounted thereon 'b'y"boltan'd nut'M passing throu'ghthe elongatedslot in arm and elongated slot 46 in yoke '43. "Thus, each of the arms is mounted in such a manner that it can be moved as 'desiredto providethe correct flexing of the sheet. Rolls lllbear upon the upper face of the 'flatportionofthe sheet.

Backing rolls ll can be carried on rollerbear 4 ings 48 which in turn can be mounted on carriers 49. Carriers 59 may have square or suitable shaped apertures through which pass the laminated or flexible shaft or support 50. Support 50 is so arranged that it can be suitably flexed in accordance with the desired curvature to which the sheet is to be bent .or flexed. rSpacers 58 can "be providedbetween theiabackingar'olls as needed.

The ends of support 50 can be held by bolts 5| in brackets 52, brackets 52 being in effect pivoted at point v53 of the abutment 54. Point 53 of abutment 53 is engageable in a suitable notch 55 in the arms of yoke 43. Nuts 56 and lock nuts '51 can be-provided in order to suitably adjust the mechanism according to the curvature desired.

It is to be understood that parts of the combination can be used and that variations may be made inthe details of construction without departing from the spirit of the invention except as defined in the appended claims.

What is claimed is:

.1. In an apparatus for producing flat. integrally stiffened sheets having projecting ribs 1 from .a slit tube; the combination including tube-flatteningmeans receiving. said slittube and-atleast partiallyflattening the same, roller die means having roll meansexerting pressurebetweensaid ribs on the rib side of said-asheet: andcloselya'djacent where said ribs join said sheet, andbacking means on the smooth side oftheribbed sheet opposing said roller die means.

2. Inan apparatusforproducing flat integrally stiffened sheets having projecting-ribs from :aslit tuba-the combination including tube flattening meansreceiving said slittube and: at least;.p.artially flattening the same; rollerdie means having roll means extending :between saidrribs. exerting pressure on the rib side-of the sheet closeutopthe points where said cribs join said: sheet, ri'means simultaneously exerting pressure:onsaid ribs in the same directionas'that of the; pressureczapplied to the sheet; andbacking roll meanscbearing 5 against the smooth J side :of" the ribbed? sheet opposing said rolleradiemeans.

:3.'In an apparatus for-producing flatL-integral'ly stiffened sheets lhavin'g 1 projecting T1198 from a slit tube, the.conrbinationincludingl tube flattening means receiving-said slit i tube and at least .partially flattening the same, "roller 'die means. having roll :meansextending betweensaid ribs sand exertingpressure on said sheet, said roller: die means having a plurality 'of'r'o'lls extending between'sai'd ribs and: contacting the rib side ofsaid sheet closely -adjacent the joinder point of said ribswith said sheet and exciting pressure thereon, backing roll means bearing against the opposite sideof thesheet and having relieved portions opposite said ribs, androll means exerting pressure onsaid ribs in" the same direction as that of the pressure on the sheetatthe same time as said roller die'means so as'to' flatten said sheet.

4. In an'apparatus for'o'perating on integrally stifiened sheets having projecting ribs,- the combination including aplurality of rolls z'having sheet contacting "surfaces passable between the ribs for contacting the flat surface of the sheet, means adjustably supportingeach of. said rolls so. that the sheet contacting surfaces vciitherolls will-define a predetermined curvature, backing rolls. for the aforementioned: rolls,=.carrier .means for each of said backing-rollssaid carrier :means having-an aperture therethrough,.--.-andea flexible "shaft means passing through said carrier means and supporting said backing rolls in the desired curvature in relation to said first mentioned rolls.

5. The method of forming a fiat integrally stiiTened sheet member having a sheet portion and a plurality of integral substantially parallel ribs projecting therefrom, comprising the steps of slitting a tube having ribs extending radially from the Wall of said tube, then flattening the ribbed Wall by exerting pressure on the rib side of said sheet portion at the surface thereof close- 1y adjacent to the points where the ribs join the sheet portion, and at the same time exerting pressure on said ribs toward said sheet while supporting said sheet portion on the side of said sheet opposite to the ribs.

6. The method of forming a flat integrally stiffened sheet member having a plurality of integral projecting ribs, comprising the steps of slitting a tube having ribs radially extending from the wall of said tube, progressively opening said slit tube and flattening said ribbed wall by exerting pressure thereon close to the points where the ribs join the wall on the rib side of said wall while supporting the opposite side of said wall, and thereafter flexing said wall in a direction opposite to its curvature as a tube.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 837,707 Mouterde Dec. 4, 1906 904,451 Richards Nov. 17, 1908 1,133,903 Wright Mar. 30, 1915 1,485,313 Taylor Feb. 26, 1924 1,521,065 Barme Dec. 30, 1924 1,716,362 Billigham June 11, 1929 1,914,439 Langford June 20, 1933 2,037,608 Walker Apr. 14, 1936 2,098,989 Yoder Nov. 16, 1937 2,201,173 Hanitz May 21, 1940. 2,313,702 Allen Mar. 9, 1943 2,458,686 Davie, Jr Jan. 11, 1949 FOREIGN PATENTS Number Country Date 103,215 Great Britain Jan. 18, 1917 426,768 Germany Mar. 16, 1926 556,061 Great Britain Sept. 17, 1943 

